Wall barricades are fortifications that may be crafted by combining two Wooden Planks, two Nails, and a Hammer in the crafting screen. Once crafted, they may be placed within the world by selecting them, and then clicking on the desired tile; a hammer is not needed for this. Take care when placing them, as they are not possible to remove. The only way to destroy these are for zombies to do it or to burn it via oven or Molotov.

Barricade world

A wall barricade in action.